Optimization of thermal performance in ceramic microchannel heat exchangers using alumina-water nanofluids: a hybrid MCDM approach

The thermal performance of microchannel heat exchangers (MCHEs) is significantly affected by fabricating materials and working fluids. However, studies combining advanced ceramics and nanofluids for optimizing heat transfer effectiveness are limited. This study addresses this gap by synthesizing two ceramic composites, ZrB2-HfB2-SiC-Cf and TiB2-SiC-Cf, using spark plasma sintering and evaluating their microstructure, phase composition, and thermal properties. Numerical simulations were performed in ANSYS Fluent 2024 R1 to examine the influence of fabricating materials, mass flow rates, and alumina-water nanofluid concentrations on MCHE performance. The simulations, validated against previous experimental data, utilized steady-state heat transfer and fluid dynamics equations. A multi-criteria optimization approach integrating grey relational analysis, response surface methodology, and the entropy mass method was employed. Results indicated that higher alumina concentrations and mass flow rates enhanced heat transfer but increased pressure drop, affecting efficiency. The optimal configuration, achieved using ZrB2-HfB2-SiC-Cf, a 30 kg h-1 mass flow rate, and a 3 mass% alumina concentration, provided the best balance between heat transfer and pressure drop.This research demonstrates the potential of advanced ceramics and nanofluids to improve MCHE performance and establishes the hybrid GRA-RSM approach as an effective tool for optimizing design parameters in industrial applications.